The Michael reaction is a known process wherein a Michael acceptor (such as an .alpha.,.beta.-ethylenically-unsaturated aldehyde, ester, nitrile, ketone, sulfone, or sulfoxide) is reacted with a Michael donor (such as a dialkyl malonate) to elongate a carbon chain. U.S. Pat. No. 2,396,626 (Wiest et al.) teaches that useful products can be obtained by reacting two molecules of acrylonitrile, an alkyl acrylate, or an acrylamide with a molecule of a donor, such as an ester, amide, or nitrile of malonic acid, phenylacetic acid, cyanoacetic acid, or acetoacetic acid. However, as indicated in Skarzewski, "The Michael Reaction of Methanetricarboxylic Esters. A Simple Method for Two-Carbon Chain Elongation," Synthesis, December 1990, pp. 1125-1127, it has usually been considered undesirable to add a donor molecule to more than one acceptor molecule in such a reaction.